Reapply r213647 with a fix.
ASTMatchers currently have problems mixing bound TypeLoc nodes with Decl/Stmt
nodes. That should be fixed soon but for this checker there we only need the
TypeLoc to generate a fixit so postpone the potentially heavyweight AST walking
until after we know that we're going to emit a warning.
This is covered by existing test cases.
Original message:
[clang-tidy] Add a check for RAII temporaries.
This tries to find code similar that immediately destroys
an object that looks like it's trying to follow RAII.
{
scoped_lock(&global_mutex);
critical_section();
}
This checker will have false positives if someone uses this pattern
to legitimately invoke a destructor immediately (or the statement is
at the end of a scope anyway). To reduce the number we ignore this
pattern in macros (this is heavily used by gtest) and ignore objects
with no user-defined destructor.
llvm-svn: 213738
diff --git a/clang-tools-extra/clang-tidy/misc/UnusedRAII.h b/clang-tools-extra/clang-tidy/misc/UnusedRAII.h
new file mode 100644
index 0000000..6850ab9
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/UnusedRAII.h
@@ -0,0 +1,47 @@
+//===--- UnusedRAII.h - clang-tidy ------------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_RAII_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_RAII_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+
+/// \brief Finds temporaries that look like RAII objects.
+///
+/// The canonical example for this is a scoped lock.
+/// \code
+/// {
+/// scoped_lock(&global_mutex);
+/// critical_section();
+/// }
+/// \endcode
+/// The destructor of the scoped_lock is called before the critical_section is
+/// entered, leaving it unprotected.
+///
+/// We apply a number of heuristics to reduce the false positive count of this
+/// check:
+/// - Ignore code expanded from macros. Testing frameworks make heavy use of
+/// this.
+/// - Ignore types with no user-declared constructor. Those are very unlikely
+/// to be RAII objects.
+/// - Ignore objects at the end of a compound statement (doesn't change behavior).
+/// - Ignore objects returned from a call.
+class UnusedRAIICheck : public ClangTidyCheck {
+public:
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_RAII_H